Soft X-ray induced radiation damage in thin freeze-dried brain samples studied by FTIR microscopy

In order to push the spatial resolution limits to the nanoscale, synchrotron-based soft X-ray microscopy (XRM) experiments require higher radiation doses to be delivered to materials. Nevertheless, the associated radiation damage impacts on the integrity of delicate biological samples. Herein, the extent of soft X-ray radiation damage in popular thin freeze-dried brain tissue samples mounted onto Si3N4 membranes, as highlighted by Fourier transform infrared microscopy (FTIR), is reported. The freeze-dried tissue samples were found to be affected by general degradation of the vibrational architecture, though these effects were weaker than those observed in paraffin-embedded and hydrated systems reported in the literature. In addition, weak, reversible and specific features of the tissue–Si3N4 interaction could be identified for the first time upon routine soft X-ray exposures, further highlighting the complex interplay between the biological sample, its preparation protocol and X-ray probe

Mercury in waste products from hard coal processing plants

Rtęć dość powszechnie występuje zarówno w węglu brunatnym, jak i kamiennym. Uważa się, że w substancji mineralnej węgla powiązana jest ona głównie z pirytem, a w substancji organicznej z grupami tiolowymi. Niemniej jednak spotykane są również węgle, w których rtęć w znacznych ilościach powiązana jest z węglanami i krzemianami. Można by zatem oczekiwać, że ilość występującej w węglu rtęci powinna być skorelowana z zawartością substancji mineralnej czy zawartością popiołu. Jednak w literaturze informacje na temat takiej korelacji są sprzeczne.W niektórych pracach stwierdzono, że rosnącej zawartości popiołu towarzyszy zwiększona zawartość rtęci, natomiast w innych taka prawidłowość nie była obserwowana. Celem pracy było wyjaśnienie powiązania między występowaniem rtęci i siarki w substancji mineralnej polskich węgli kamiennych. W tym celu przebadano populację odpadów z procesu wzbogacania węgli kamiennych, charakteryzujących się relatywnie niską zawartością substancji organicznej. Wyjaśnienie sposobu powiązania rtęci i siarki w substancji mineralnej posiada nie tylko aspekt poznawczy, ale może być też wykorzystane dla optymalizacji procesów usuwania rtęci z węgla, jak też może być pomocne dla opracowania i udoskonalenia aktualnie stosowanych metod zagospodarowania odpadów górniczych. [...]Mercury is commonly found in hard coals and lignite. It is believed, that mercury occurs in coal both in mineral matter, mainly in pyrite, and also in organic matter, in thiols groups. Nevertheless, there are coals in which mercury occurs in large amounts in silicates and carbonates. Therefore, it could be supposed, that mercury should be correlated with mineral matter and ash content. In literature contradictory information can be found. There are coals, in which mercury content grows, with an increase in ash content. However, examples can also be found where that kind of correlation was not noticed. The aim of this study was to explain the relationship between the occurrence of mercury and sulfur in the mineral matter of Polish hard coals. For this purpose, waste products from the hard coal processing plants were examined. These wastes are characterized by a low organic matter content. The explanation of the mode of occurrence of mercury in mineral matter could be useful for optimizing the method of mercury content reduction in coal and also for optimizing waste products utilization techniques. [...

Changes in the concentration of mercury in hard coal in the coal washing process

Rtęć i jej związki zalicza się do bardzo niebezpiecznych substancji. Do głównych źródeł emisji rtęci spowodowanych działalnością człowieka zalicza się procesy spalania paliw kopalnych, głównie węgla. Istnieje szereg metod pozwalających ograniczyć emisję rtęci z tych procesów. Metody te można podzielić na dwie główne grupy. Do pierwszej zaliczane są metody polegające na usuwaniu rtęci ze spalin, a do drugiej należą metody polegające na obniżeniu zawartości rtęci w węglu przed jego wykorzystaniem. Do tej grupy zalicza się proces wzbogacania węgla. Celem prezentowanego artykułu było określenie zmiany zawartości rtęci w wybranych polskich węglach kamiennych w procesie ich wzbogacania. Dla potrzeb realizacji pracy przeanalizowano wytypowane przemysłowe urządzenia do wzbogacania węgla. Dla każdego urządzenia zbadano nadawę i koncentrat. W świetle uzyskanych wyników można stwierdzić, że proces wzbogacania nie zawsze pozwala na obniżenie zawartości rtęci w węglu. Niemniej jednak, uwzględniając polepszenie jakości węgla wskutek obniżenia w nim zawartości substancji mineralnej, uzyskuje się zadowalające rezultaty. Obniżenie zawartości substancji mineralnej, powoduje znaczny wzrost jego kaloryczności, a tym samym zmniejszenie jego jednostkowego zużycia, co z kolei pozwoli na zmniejszenie ilości emitowanej do środowiska rtęci. Uzyskane skuteczności w obniżeniu zawartości rtęci przy uwzględnieniu wzrostu kaloryczności węgla wynosiły od 10 do 89%. Najwyższe jej wartości uzyskano dla wzbogacania w płuczce zawiesinowej cieczy ciężkiej.Mercury and its compounds are classified as extremely hazardous substances. The main sources of mercury emissions caused by human activities are the combustion processes of fossil fuels – mainly coal. There are several methods which enable a reduction in mercury emissions from these processes. They can be classified under two main groups. The first group includesmethods for removing mercury from exhaust gases (post-combustion methods). The second group includes methods of reducing the mercury content in coal before its utilization (pre-combustion methods). The coal washing process is classified under the second group of methods. The aim of this paper was to determine the changes in the mercury content in hard coal in the coal washing process. Coal samples obtained in hard coal processing plants were analyzed. For each case, raw and clean coals were examined. In view of the results, it can be concluded that the coal washing process does not lead to a reduction of mercury content in all cases. However, taking into account the improvement in coal quality as a result of a reduction of themineralmatter content, the results obtained were promising. The reduction of mineral matter causes a significant increase in caloric value. A higher calorific value of coal will reduce its consumption and, thus, will reduce the amount of mercury emitted into the environment. The determined ratios of mercury content reduction ranged from 10 to 89%. The highest ratios were obtained for dense media baths

The influence of electrical stimulation of vagus nerve on elemental composition of dopamine related brain structures in rats

Recent studies of Parkinson s disease indicate that dorsal motor nucleus of nerve vagus is one of the earliest brain areas affected by alpha synuclein and Lewy bodies pathology. The influence of electrical stimulation of vagus nerve on elemental composition of dopamine related brain structures in rats is investigated. Synchrotron radiation based X ray fluorescence was applied to the elemental micro imaging and quantification in thin tissue sections. It was found that elements such as P, S, Cl, K, Ca, Fe, Cu, Zn, Se, Br and Rb are present in motor cortex, corpus striatum, nucleus accumbens, substantia nigra, ventral tectal area, and dorsal motor nucleus of vagus. The topographic analysis shows that macro elements like P, S, Cl and K are highly concentrated within the fiber bundles of corpus striatum. In contrast the levels of trace elements like Fe and Zn are the lowest in these structures. It was found that statistically significant differences between the animals with electrical stimulation of vagus nerve and the control are observed in the left side of corpus striatum for P p 0.04 , S p 0.02 , Cl p 0.05 , K p 0.02 , Fe p 0.04 and Zn p 0.02 . The mass fractions of these elements are increased in the group for which the electrical stimulation of vagus nerve was performed. Moreover, the contents of Ca p 0.02 , Zn p 0.07 and Rb p 0.04 in substantia nigra of right hemisphere are found to be significantly lower in the group with stimulation of vagus nerve than in the control rat

Sodium, potassium, chloride, and bicarbonate-related effects on blood pressure and electrolyte homeostasis in deoxycorticosterone acetate-treated rats

Na(+) loading without Cl(-) fails to increase blood pressure in the DOCA model. We compared the changes in the total body (TB) effective Na(+), K(+), Cl(-), and water (TBW) content, as well as in intracellular (ICV) or extracellular (ECV) volume in rats receiving DOCA-NaCl, DOCA-NaHCO3, or DOCA-KHCO3. We divided 42 male rats into 5 groups. Group 1 was untreated, Group 2 received 1% NaCl, Groups 3, 4, and 5 were DOCA-treated and received 1% NaCl, 1.44% NaHCO3, or 1.7% KHCO3 to drink. We measured mean arterial blood pressure (MAP) after 3 weeks directly. Tissue electrolyte and water content was measured by chemical analysis. Compared to controls, DOCA-NaCl increased MAP, while DOCA-NaHCO3 and DOCA-KHCO3 did not. DOCA-NaCl increased TBNa(+) 26% but only moderately increased TBW. DOCA-NaHCO3 led to similar TBNa(+) excess, while TBW and ICV, but not ECV, were increased more than in DOCA-NaCl rats. DOCA-KHCO3 did not affect TBNa(+) or volume. At a given TB(Na(+)+K(+)) and TBW, MAP in DOCA-NaCl rats was higher than in control, DOCA-NaHCO3, and DOCA-KHCO3 rats, indicating that hypertension in DOCA-NaCl rats was not dependent on total body (Na(+)+K(+)) and water mass balance. Skin volume retention was hypertonic compared to serum and paralleled hypertension in DOCA-NaCl rats. These rats had higher TB(Na(+)+K(+))/TBW ratio in accumulated fluid than DOCA-NaHCO3 rats. DOCA-NaCl rats also had increased intracellular Cl(-) concentrations in skeletal muscle. We conclude that excessive cellular electrolyte redistribution and/or intracellular Na(+) or Cl(-) accumulation may play an important role in the pathogenesis of salt-sensitive hypertension. Key words: hypertension, Na storage, hypertonicity, iso-osmolality, intracellular chloride

Soft X-ray induced radiation damage in thin freeze-dried brain samples studied by FTIR microscopy

In order to push the spatial resolution limits to the nanoscale, synchrotron-based soft X-ray microscopy (XRM) experiments require higher radiation doses to be delivered to materials. Nevertheless, the associated radiation damage impacts on the integrity of delicate biological samples. Herein, the extent of soft X-ray radiation damage in popular thin freeze-dried brain tissue samples mounted onto Si3N4 membranes, as highlighted by Fourier transform infrared microscopy (FTIR), is reported. The freeze-dried tissue samples were found to be affected by general degradation of the vibrational architecture, though these effects were weaker than those observed in paraffin-embedded and hydrated systems reported in the literature. In addition, weak, reversible and specific features of the tissue–Si3N4 interaction could be identified for the first time upon routine soft X-ray exposures, further highlighting the complex interplay between the biological sample, its preparation protocol and X-ray probe

A sodium-bicarbonated mineral water reduces gallbladder emptying and postprandial lipaemia: A randomised four-way crossover study

S.A Vichy Catalán. SpainPeer reviewe